Enthralling Storage Properties of (1–x)La_0.03Na_0.91NbO₃–xBi(Li_0.5Nb_0.5)O₃ Lead-Free Ceramics: High Energy Storage Applications

Abstract

The current work presents the designed series of compositions within pseudocubic regions based on (1−x)La 0.03 Na 0.91 NbO 3 −xBi(Li 0.5 Nb 0.5 )O 3 ceramics abridged as (1−x)LNN−xBLN meant for energy storage applications. The addition of Bi(Li 0.5 Nb 0.5 )O 3 (BLN) considerably disrupted the ferroelectric order of the La 0.03 Na 0.91 NbO 3 (LNN) ceramics and favored the perfection of the energy storage density properties. Material properties like breakdown strength (BDS), charge−discharge efficiency (η), and dielectric loss of the system were enhanced via the incorporation of BLN into LNN. The external electric field supply into the system drastically enlarged the energy storage density, where the maximum recoverable energy density value of 2.02 J cm −3 at 300 kV cm −1 was achieved in 0.88LNN−0.12BLN ceramics. Besides this, the new system also demonstrates a strong ability to withstand stress (fatigue-free character) and sound temperature stability characteristics. The impressive storage density, temperature stability, cycle stability, and frequency stability credited to a steady relaxor pseudocubic phase covering a broad temperature range describes the newly designed system. The results demonstrate the potential for the (1−x)LNN−xBLN ceramics as the promising lead-free energy storage materials.

Significantly Enhanced Energy Storage Density of NNT Ceramics Using Aliovalent Dy3+ Dopant

“…Analysis of the microstructures reveals that DNNT grains are inhomogeneous and their average grain size decreases on increasing the level of the dopant up to x = 0.2 mol, and above 0.2 mol, the growth of the grain appears, as shown in Figure a–e. The decreasing grain size with the increase of the Dy 3+ ions suggests that a limited amount of up to 0.2 mol of Dy 3+ ion is enough to enhance the microstructure desired for storage purposes, above which deterioration of the storage character, in this case, grain size, which is inversely related to the breakdown strength of the materials, in question is assured . The grain size for various x contents is as follows: for 0, 0.05, 0.1, 0.2, and 0.3 it is 5.22 ± 0.2, 1.44 ± 0.2, 1.31 ± 0.2, 1.10 ± 0.2, and 1.44 ± 0.2 μm, respectively, as shown in Figure f.…”

“…It has been reported that for a dielectric to be practically used, it must be stable over a wide range of frequency supply . The DNNT20 frequency stability was studied and reported in Figure a,b.…”

“…The decreasing grain size with the increase of the Dy 3+ ions suggests that a limited amount of up to 0.2 mol of Dy 3+ ion is enough to enhance the microstructure desired for storage purposes, above which deterioration of the storage character, in this case, grain size, which is inversely related to the breakdown strength of the materials, in question is assured. 45 The grain size for various x contents is as follows: for 0, 0.05, 0.1, 0.2, and 0.3 it is 5.22 ± 0.2, 1.44 ± 0.2, 1.31 ± 0.2, 1.10 ± 0.2, and 1.44 ± 0.2 μm, respectively, as shown in Figure 3f. The displayed grain size average shows that Dy 3+ ion restricts grain growth, thereby suppressing the grain size to about several micrometers as displayed in Figure 3f.…”

“…Furthermore, broadening of the peak to become flattened with increasing x is seen in Figure 6a,b, which may be due to the aliovalent nature of cations in DNNT composition, i.e., the differences in the radius and the valence of Dy 3+ cations from those of Na + at the A site disrupt the ferroelectric nature of NNT and promote the formation of a local polar region in DNNT. 45 The cationic disorderliness in DNNT caused a relaxor behavior (P−E loops became thinner with increasing Dy 3+ ) in the ceramics. The relaxor properties of the materials can be explained using a modified Curie−Weiss law as follows…”

“…It has been reported that for a dielectric to be practically used, it must be stable over a wide range of frequency supply. 45 The DNNT20 frequency stability was studied and reported in Figure 5a,b. The results presented show that the material withstands frequencies of up to 100 Hz where a slight decrease in P max is evidenced.…”